Inductor for the thermal treatment of a material which is not very or non-electrically conducting containing ferromagnetic or electrically conductive particles

ABSTRACT

An inductor for use in the thermal treatment of a material which is not very or non-electrically conducting containing ferromagnetic or electrically conductive particles. The inductor forms, in combination with the insulation between its conductors, a mold in which the material containing ferromagnetic or electrically conductive particles is submitted to the thermal treatment.

United States Patent Binard 3,705,2 4 Dec. 5, 1972 2,875,556 Vigna'eta1. 3,126,937 3/1964 Brower et a1.

INDUCTOR FOR THE THERMAL 219/1057 x .219/7.s x .219/10.49 x........219/1o.s3 x ........219/1o.41x .......219/1o.s3 x

.. ....l8/38 X .......18/38 x ...219/10.ss

TREATMENT OF A MATERIAL WHICH IS NOT VERY OR NON- l,380,2-50 5/1921Reymond ELECTRICALLY CONDUCTING 2,372,929 1945 CONTAINING FERROMAGNETIC()R 2,393,541 1/1946 Kohler....... ELECTRIC ALLY CONDU 2,438,952 4/1948' Grotenhuis PARTICLES 2,581,939 1/1952 Deist [72] I t 9/1952Seifried nven or:

2,611,152 Pierre C. Blnard, Embourg, Belgium 2,738,406 3,391,846

3/1956 Zaleski...............

7/1968 White.........

[73] Assignee: Elphiac, Bruxelles, Belgium [22] Filed:

1970 Primary Examiner-J. V. Truhe Assistant Examiner-Hugh D. JaegerAtt0rneyRaymond A, Robic [21] Appl. No.: 13,434

ABSTRACT [30] Foreign Application Priority Data Feb. 27, 1969Belgium....,.............................70,585

tive particles. The inductor forms, in combination with the insulationbetween its conductors, a mold in which the material containingferromagnetic or electrically conductive particles is submitted to thethermal treatment.

[51] Int..-Cl.........

8 Claims, 3 Drawing Figures [5 6] References Cited UNITED STATES PATENTS2,014,332 9/1935 Houlette...........................219/535 X 7/ 1 w ti2 USN PATENTEDHEI: 51972 FIG.2

INVENTOR Pierre '6. BINARD ATTORNEY PATENTEDun: sum V A 3.705.284

' sum 2 or 2 FIG. 3

INVENTOR Pam c. BINARD INDUCTOR FOR THE THERMAL TREATMENT OF A MATERIALWHICH IS NOT VERY OR NON- ELECTRICALLY CONDUCTING CONTAININGFERROMAGNETIC OR ELECTRICALLY CONDUCTIVE PARTICLES The invention relatesto an inductor for'use in the thermal treatment of a material which isnot very or non-electrically conductive containing ferromagnetic orelectrically conductive particles.

It is known in the art to incorporate powders of magnetite, offerromagnetic metals, or of electrically conductive materials insubstances which are not very or non-electrically conductive and tosubmit these mixtures to an electromagneticalternating field so as toheat them in order to render them fluids, to vulcanize them, topolymerize them or to dry them etc.-

The object of the invention is to provide an inductor for use with sucha known process, wherein the thermal treatment of the materialcontaining ferromagnetic or electrically conductive particles is carriedout in'a receptacle such as a mold, the chamber of a screw type pump, adye etc. v

The inductor, in accordancewith the invention, is characterized in thatit forms, in combination with the insulation between its conductors, themold in which the material containing ferromagnetic or electricallyconductive particles is submitted to the thermal treatment.

The invention will now, be disclosed with reference to two embodimentsthereof and to the accompanying drawings in which:

FIGS. 1 and 2 illustrate similar arrangements of a first inductor inaccordance with the invention; and

FIG. 3 illustrates a second embodiment of aninductor in accordance withthe invention.

In FIG. 1, there is shown two half molds l and 2 which are electricallyconductive and made of, for example, cast aluminum. The half molds haveroughly the shape of a hollow torus separated in two through its planeof symmetry perpendicular to the axis 3 thereof. However, the two halfmolds are not necessarily perfectly 'symmetricaL'An insulating ring 4ispositioned between the two inside mating edges of the half molds 1 and 2and provides an electrical insulation between the current feedingconductors. The ring 4 includes an opening therein through which maypetrude a pipette (not shown) for permitting to build up a pressure thetwo half molds once assembled. The insulating ring 4 may be made of anelastomer which is resistant to high temperatures. The outside matingedges of the two half molds l and 2 include means to ensure a goodelectrical contact between such edges such as, for example, a smallprojection 5 on the half mold 2 along the inside circumference thereof.When the two half molds 1 and 2 are made of aluminum, the contactsurface of projection 5 and the opposite contact surface of the halfmold l are coated with a thin layer of a material the conductingproperties of which are not impaired by sulphur such as, for example,gold.

It is also possible to provide a series of contact springs 6 located atequal distances along the inside circumference of the outside edge ofone of the two half molds such as, for example, the half mold 2 asillustrated in FIG. 2. These contact springs 6 may be made of bronze andmay bear on a copper band 7 inserted into the other half mold l.

The two half molds l and 2 are connected at their inside edges to twohigh frequency current feeding conductors 8 and 9. These conductors mayconsist of two sleeves providing a uniform electrical contact along theinside edge of each half mold or may consist of a number of contactfingers equally spaced along the inside edges of the half molds.

The high frequency current is generated, preferably, by a transformer 10located adjacent to the torus. In accordance with a first embodiment,which is particularly advantageous for the manufacture of vehicle tires,the transformer 10 is a toroidal transformer comprising an insideprimary winding made of a number of turns of conductors and an outsidesecondary winding 12 consisting of a torus cut along two parallelcircles and welded at the location of such cut to the two sleeves 8 and9. The sleeve 9 may be permanently connected to half mold 2 by means ofscrews, for example, protruding through a flange 13 of the sleeve, whilethe edge of the other sleeve 8, which is to contact the half mold 1, maybe slit so as to form a number of contact fingers 14 which are appliedagainst the half'mold 1 by means of :1 conical piston 15 operated by apneumatic device 16.

Inside the hollow torus, there are provided shaped pieces made of anelectrically non-conducting material which is'also heat resistant. Suchpieces may be made, for example, of a material known under the trademark Araldite containing quartz and resistant to at least C. It is alsopossible to make such pieces of a thermosetting material containing aferromagnetic or electrically conductive powder. In addition, thesepieces may be reinforced by glass fibers or by textiles of the samematerial.

In FIG. 3, there is shown an alternative embodiment of the invention.

In such embodiment, a spiral inductor having a solid conductor 17 issurrounded by a layer of an insulating material 18 such as, for example,polytetrafluorethylene known under the trade mark Teflon. The insulatingmaterial 18 fully surrounds the conductor 17 and has an inside surfacewhich is suitable for a mold. The assembly of the inductor and of theinsulating material is supported by a reinforcing outside tube 19 madeof, for example, porcelain. Such tube 19 may be replaced by the jaws ofa clamping tool since the use thereof is to prevent inductor 17 fromopening up when a pressure is established inside the mold. When thepressure is nil or very low, outside clamping means such as tube 19 arenot necessary. In order to permit molding inside inductor 17, a lowerpiston 20 and an upper piston 21 are provided. These pistons may bemade, preferably, of a material which is electrically and thermallyinsulating. However, it is also possible to provide pistons which areelectrically conducting or having sufficient magnetization losses toproduce about the same amount of heating than that produced in thematerial to be treated.

It is also possible to provide a conductor 17 which is 1 hollow so as topermit circulation of water or vapor inside the conductor, in order toalways maintain the conductor at a predetermined temperature which maybe chosen to be about equal to that of the material undergoing a thermaltreatment inside the inductor.

I claim:

1. An inductor for use in the thermal treatment of a material which isrelatively poorly electrically conducting shaped pieces located insidethe half molds and made of a thermosetting material which is nonelectrically conducting.

3. An inductor as defined in claim 2, wherein said thermosettingmaterial is Araldite which is resistant to at least 150C.

4. An inductor as defined in claim 1, wherein the means ensuring apositive electrical contact between the outside edges of said half moldscomprise contact springs located at equal distances along the insidecirprojection along the inside circumference of the out-- side edges ofsad half molds.

6. An inductor as defined in claim 5, wherein a thin coating of a metalthe conducting properties of which are not impaired by sulphur aredisposed along the mating outside edges of said half molds.

7. An inductor as defined in claim 1, wherein said high frequencycurrent source comprises a transformer having a primary winding and asecondary winding located adjacent to the torus formed by said halfmolds, and wherein the current conductors connected to the inside edgesof said half molds are the ends of the secondary winding of saidtransformer.

8. An inductor as defined in claim 13, wherein said transformer is atoroidal transformer which is connected to said half molds by means oftwo concentric sleeves.

1. An inductor for use in the thermal treatment of a material which isrelatively poorly electrically conducting and containing electricallyconductive particles comprising two electrically conductive half moldshaving the shape of a hollow torus separated through its plane ofsymmetry perpendicular to the axis of the torus, an insulating ringpositioned between the two inside mating edges of said half molds, meansfor insuring a positive electrical contact between outside mating edgesof said half molds, and current feeding conductors connected to theinside edges of said half molds and adapted for connection to a sourceof high frequency current.
 2. An inductor as defined in claim 1, furthercomprising shaped pieces located inside the half molds and made of athermosetting material which is non electrically conducting.
 3. Aninductor as defined in claim 2, wherein said thermosetting material isAraldite which is resistant to at least 150*C.
 4. An inductor as definedin claim 1, wherein the means ensuring a positive electrical contactbetween the outside edges of said half molds comprise contact springslocated at equal distances along the inside circumference of the outsideedges of said half molds.
 5. An inductor as defined in claim 1, whereinthe means ensuring a positive electrical contact between the outsideedges of said half molds comprise a small projection along the insidecircumference of the outside edges of sad half molds.
 6. An inductor asdefined in claim 5, wherein a thin coating of a metal the conductingproperties of which are not impaired by sulphur are disposed along themating outside edges of said half molds.
 7. An inductor as defined inclaim 1, wherein said high frequency current source comprises atransformer having a primary winding and a secondary winding locatedadjacent to the torus formed by said half molds, and wherein the currentconductors connected to the inside edges of said half molds are the endsof the secondary winding of said transformer.
 8. An inductor as definedin claim 13, wherein said transformer is a toroidal transformer which isconnected to said half molds by means of two concentric sleeves.